1. Field of the Invention
The present invention relates to a charge and discharge test probe for a secondary battery, the probe enabling stable testing by having an increased contact area with respect to an electrode terminal of a secondary battery.
2. Description of the Prior Art
Secondary battery is a generic term for batteries that can be repeatedly recharged unlike primary batteries that cannot be recharged. Secondary batteries are widely used in electronic devices such as mobile phones, laptop computers, MD players, general computers, and camcorders because they enable electronic devices to be smaller and lighter, exhibit high operation stability even while undergoing repeated charging and discharging, and can be freely recharged without a memory effect.
A lithium secondary battery, which is a secondary battery, includes a case and an electrode assembly rolled in the case, in which the electrode assembly includes a positive plate and a negative plate that are alternately arranged with a separator interposed therebetween. In addition, a liquid electrolyte is contained in the case so as to soak into the electrode assembly. Secondary batteries can be provided in various shapes, for example, a prismatic shape, a cylindrical shape, or a pouch shape.
One of the major factors indicating the performance of a secondary battery is current capacity during discharge. Current capacity of secondary batteries having same specifications needs to rarely vary or vary within a small and predetermined distribution range. For this reason, all of the produced secondary batteries undergo test of electrical characteristics including, for example, a charge and discharge test, and defective products determined through the test are removed.
FIG. 1 of Korean Patent Application Publication No. 10-2011-0045890 (titled “Secondary Cell Charge-Discharge Test Probe for Applying Voltage and Current”) discloses a conventional probe.
The conventional test probe shown in FIG. 1 is a voltage and current application-type charge and discharge test probe for a secondary battery. The conventional test probe includes: a cylindrical outer body that can be elastically moved up and down; an outer plunger combined with an end of the outer body; an inner body installed in the outer body and elastically moved up and down; an inner plunger combined with an end of the inner body, spaced from the outer plunger, and elastically moved up and down; and an insulator electrically insulating the inner plunger, the inner body, and the outer body from each other, wherein the outer plunger is detachably combined with the end of the outer body, either an upper end of the inner body or a lower end of the inner plunger is provided with one or more elastic recesses, either the upper end of the inner body or the lower end of the inner plunger is provided with a concave portion, and the inner plunger is detachably combined with the end of the inner body by press-fitting the one or more elastic recesses into the concave portion.
The conventional test probe includes heads 101 and 901 respectively provided with contact portions 101 and 902 on the upper surfaces thereof. The contact portions 102 and 902 have a predetermined size and respectively include a voltage terminal 102 and a current terminal 902 on planar surfaces. In the process of producing lithium ion batteries that are secondary batteries, or other kinds of batteries, the current terminal 902 encounters a problem associated with current capacity. In addition, during a battery charge and discharge test, the contact portions 102 and 902 obliquely come into contact with an electrode terminal of a secondary battery. Therefore, a contact with the electrode terminal becomes unstable, resulting in contact failure, which makes it difficult to stably apply a voltage or a current to the electrode terminal.